Health monitoring of feedback controlled mechatronic systems

Health monitoring is essential in guaranteeing the safe, efficient, and correct operation of complex engineering systems. This PhD thesis presents a simulation of a non-linear, experimental-based model of a coupled tank apparatus CE105 under LabVIEW environment. The consideration of a traditional simple tank system is extended via the inclusion of non-linear elements. The simulation is used to accelerate the timescales of the monitoring and controller signals for nominal and faulty behaviour for several operating scenarios. In this study, a detailed simulation with several sources of fault was produced and run with the variety of operating scenarios to study the nominal and faulty behaviour of such mechatronic system. It is concluded that the liquid level will not be affected by fault nature and intensity in the presence of PID controller that covers hidden faults until its signal reaches a certain threshold. Hence, the end of useful life can be predicted by tracking the PID signal at any stage of the operating scenario. Technology advances have impacted upon monitoring, diagnostics and prognostics activities for increasingly sophisticated industrial systems and their operations. In particular, for integrated mechatronic systems, the facility provided by dynamic simulation models in presence of deteriorating faults has been investigated. For informed data-driven prognostic extrapolations, the long-term, time-varying operational profile of the mechatronic system requires recording and analysis. The contribution reported in this study relates to the simulation and experimentally validated, of a CE105 coupled-tank liquid level control system and three individual-thank liquid level system. A Sign Chart Algorithm (SCA) was developed and utilised as a novel controller-based health monitored (CBHM) system. Moreover, from the SCA and the PID signal trend, the remaining useful life of the system has been estimated. Results are reported and discussed for leakage or blockage and pump performance deterioration faults

Mining Safety and Sustainability I

Safety and sustainability are becoming ever bigger challenges for the mining industry with the increasing depth of mining. It is of great significance to reduce the disaster risk of mining accidents, enhance the safety of mining operations, and improve the efficiency and sustainability of development of mineral resource. This book provides a platform to present new research and recent advances in the safety and sustainability of mining. More specifically, Mining Safety and Sustainability presents recent theoretical and experimental studies with a focus on safety mining, green mining, intelligent mining and mines, sustainable development, risk management of mines, ecological restoration of mines, mining methods and technologies, and damage monitoring and prediction. It will be further helpful to provide theoretical support and technical support for guiding the normative, green, safe, and sustainable development of the mining industry

A new method for improving decisionmaking in the supply chain risk management process. Supporting the learning project management organisation by applying advanced business modelling simulation techniques

The rise of importance of supply chain risk management both, in the scientific and business world, is essentially the result of solving an economical paradox. How can an organisation continuously increase its growth in revenue and increase its profit in a world in which the flow of goods and financial means is reaching a never seen complexity? This provides both, a threat and an opportunity to those organisations. The key is how to identify, manage and prevent operational risk. The following thesis aims at providing a new approach on the subject targeting project management organisations by bringing together three different disciplines, supply chain risk management, business modelling and simulation and the concept of the learning organisation. The research is based on a literature review of the identified fields followed by an empirical assessment aiming to understand the main risks threatening a project’s supply chain, the current state of supply chain risk management and application of business modelling and simulation in practice as well as gaining an understanding how the principles of the learning organisation are lived within a project management organisation. Furthermore, the thesis is providing an exemplary approach on how a simulation model could be built assessing identified supply chain risks. The literature review, as well as the empirical assessment, conducted via the combination of questionnaire and interview, is clearly showing that, while the topic of supply chain risk management has become a constant part of the scientific discussion the real-world application, especially in the context of business modelling and simulation applying the principles of the learning organisation is still executed hesitantly. Furthermore, the thesis provides an example by which current state of the art simulation software is used to allow supply chain professionals to conduct each step of the supply chain risk management process in a virtual environment. The relevancy of the work is founded in the combination of the three fields offering a new approach to complex project management organisations in further developing their supply chain risk management capabilities

Gear wear-monitoring using acoustic emission

Acoustic emission (AE) signals have shown strong potential for gear wear monitoring, because of their capability of capturing high-frequency characteristics of tribological contacts. Gear AE signals are characterised by: i) short-time features coming from the complex surface micro-structure (asperities) and ii) slower cyclic features introduced by the gear kinematics. The combination of both properties has not been exploited yet, thus leaving a significant margin for the development of AE-based gear monitoring. This thesis hence aims at developing novel AE-based gear wear monitoring tools through the investigation of the statistical properties of gear AE as well as the physical relationships between signals and gear surface conditions. This research is organised in three steps to deliver the following objectives. Step 1 is to establish the relationship between AE signals and cyclic gear kinematics, modelled using AE cyclostationarity. Differently from the next steps, this approach purposely avoids an onerous physical model, and instead uses non-Gaussian statistics to represent the micro-structure effects on AE. Results show that the newly-developed cyclic AE features are highly correlated with wear severity. The physical modelling is tackled in step 2, which investigates the link between AE and micro-scale surface conditions, independently on gear kinematics. Two available physical models for dry contact are extended to lubricated sliding, and then tested on tribometer discs with different surface finishing. The pin-on-disc configuration avoids the complex gear kinematics, facilitating the direct study of surface effects under stable speed and load. The new physical model was able to reliably estimate roughness in a series of tests with different operating conditions. In the final step, the gear-kinematic effects modelled in step 1 are superimposed to the physical relationship between surface and signals observed in step 2 for a further investigation on the relationship between AE and gear wear. A set of experiments on degrading gears has proven that the proposed techniques are able to track gear wear along tooth profiles as it evolves in time. Furthermore, this study contributed to the understanding of the impact of surface characteristics on specific AE features, opening new avenues for further developments of AE-based gear wear monitoring

Advances in the Processing and Application of Polymer and Its Composites

This book mainly focuses on the processing and applications of polymer and its composites. With the fast development of the petroleum industry, polymer materials have been widely utilized in our daily lives. The various processing methods of polymers determine the final properties and performance of products. In addition, the introduction of different fillers, including inorganic fillers, metal oxide, natural fibers, and so on, can increase the physical and chemical properties of polymer composites, which will further broaden their practical applications. Special attention will be paid to the type of processing methods and the functional fillers on the performance of polymer composites

Pressurized CO2 Electrochemical Conversion to Formic Acid: From Theoretical Model to Experimental Results

To curb the severely rising levels of carbon dioxide in the atmosphere, new approaches to capture and utilize this greenhouse gas are currently being investigated. In the last few years, many researches have focused on the electrochemical conversion of CO2 to added-value products in aqueous electrolyte solutions. In this backdrop, the pressurized electroreduction of CO2 can be assumed an up-and-coming alternative process for the production of valuable organic chemicals [1-3]. In this work, the process was studied in an undivided cell with tin cathode in order to produce formic acid and develop a theoretical model, predicting the effect of several operative parameters. The model is based on the cathodic conversion of pressurized CO2 to HCOOH and it also accounts for its anodic oxidation. In particular, the electrochemical reduction of CO2 to formic acid was performed in pressurized filter press cell with a continuous recirculation of electrolytic solution (0.9 L) at a tin cathode (9 cm2) for a long time (charge passed 67’000 C). It was shown that it is possible to scale-up the process by maintaining good results in terms of faradaic efficiency and generating significantly high concentrations of HCOOH (about 0.4 M) [4]. It was also demonstrated that, for pressurized systems, the process is under the mixed kinetic control of mass transfer of CO2 and the reduction of adsorbed CO2 (described by the Langmuir equation), following our proposed reaction mechanism [5]. Moreover, the theoretical model is in good agreement with the experimental results collected and well describes the effect of several operating parameters, including current density, pressure, and the type of reactor used. 1. Ma, S., & Kenis, P. J. (2013). Electrochemical conversion of CO2 to useful chemicals: current status, remaining challenges, and future opportunities. Current Opinion in Chemical Engineering, 2(2), 191-199. 2. Endrődi, B., Bencsik, G., Darvas, F., Jones, R., Rajeshwar, K., & Janáky, C. (2017). Continuous-flow electroreduction of carbon dioxide. Progress in Energy and Combustion Science, 62, 133-154. 3. Dufek, E. J., Lister, T. E., Stone, S. G., & McIlwain, M. E. (2012). Operation of a pressurized system for continuous reduction of CO2. Journal of The Electrochemical Society, 159(9), F514-F517. 4. Proietto, F., Schiavo, B., Galia, A., & Scialdone, O. (2018). Electrochemical conversion of CO2 to HCOOH at tin cathode in a pressurized undivided filter-press cell. Electrochimica Acta, 277, 30-40. 5. Proietto, F., Galia, A., & Scialdone, O. (2019) Electrochemical conversion of CO2 to HCOOH at tin cathode: development of a theoretical model and comparison with experimental results. ChemElectroChem, 6, 162-172